The preterit of ser and ir ~ These two essential verbs are very irregular in the “simple past” tense. BUT – they’re exactly the same! Saying was or went, is usually written the same.
IR » Foi muito bem. It went really well.
SER » Foi muito bom. It was really good.
IR » Fui! I went!
SER » A festa foi perfeita. The party was perfect.
IR » Nós fomos à praia ontem. We went to the beach yesterday.
SER » Foi um dia daqueles. It was one of those days.
IR » Eles foram fazer compras juntos. They went shopping together.
IR » Para onde ele foi? Where did he go?
* More accurately called, the preterit indicative tense.